In presses and dies, it has been common to utilize coil metal springs that fit in cylindrical pockets in a die in order to absorb the force of various operations such as metal stamping operations. It has also been common to design rams such that they incorporate gas springs which are either associated with a manifold or self contained.
Among the objectives of the present invention are to provide an improved gas spring which effectively and efficiently provides the desired absorbing force; which includes provision for relief of excess pressure; which includes provision for relief of pressure during assembly; and which can be readily adapted for use as a self-contained spring or in series with other gas springs or in a manifold or reservoir tank.
In accordance with the invention, the self-contained gas spring comprises a cylindrical body having a base wall and an integral side wall with an open upper end defining a bore. The bore includes a lower cylindrical portion and an upper cylindrical portion of greater diameter than the lower cylindrical portion defining a shoulder. A piston of constant diameter is positioned in the bore and has a radial flange on its lower end with a wear bearing contacting the lower portion of the bore. An annular retainer is positioned on the shoulder and is adapted to be engaged by the flange on the piston. An annular end cap is threaded in the upper cylindrical portion of the bore and maintains the retainer against the shoulder. An annular lock nut is threaded in the upper portion of the bore and locks the end cap in position. Circumferential spaced radial openings are provided adjacent the periphery of the lock nut for venting gas during disassembly if any gas remains. A charging valve and a rupture plug including a pressure relief disc are provided in the base wall.